Manufacture of aldehyde-amine reaction products



Patented Nov. 26, 1929 UNITED STATES PATENT. OFFICE CLAYTON OLIN NORTH AND WINFIELD SCOTT, OF AKRON, O HIOJaASSIGNORS TO THE RUBBER SERVICE LABORATORIES (30., OF AKRON, OHIO, A CORPORATION OF OHIO Y MANUFACTURE OF ALDEHYDE-AMINE REACTION PRODUCTS No Drawing. I

The present invention is directed to the process of manufacturing certain aldehydeamine reaction products. The invention is also directed to the vulcanization of rubber by a process wherein a new compound. obtained as hereinafter described and possessing desirable characteristics for the use desired, is employed as an accelerator of the vulcanization process. The invention will be readily understood from the following specification wherein the novelty of the process is fully set forth and described. I

Various types of compounds have been described heretofore as accelerators of the rubber vulcanization process. Among such compounds are the aldehyde-amine reaction products which have been developed recently and are now widely employed for this purpose. F or example, British Patent No. 7370 of 1914 to Peachy, French Patent No. 470,833 to Bastide, and United States Patent No. 1,417,970 to Cadwell all disclose as accelerators, the use of compounds obtained by the condensation of equi-molecular proportions of aldehydes and amines. A more recent patent to North (U. S. Patent No. 1,467,984)

claims as accelerators of the rubber vulcanization process, those compounds obtained by treating the simple reaction products of aldehydes and amines first formed, that is Schiifs bases with a further quantity of an aldehyde. The process of manufacturing compounds of this type is described andvclaimed in a copending application Serial No. 627,326 filed by C. 0. North on March 24, 1923. Further more, the process of manufacturmg a product of this general type by reacting an aldehyde wit-l1 an amine in other than equi-molecular proportions and then reacting the product so formed with a further quantity of the same or a different aldehyde is claimed in another copending application Serial No. 627,325 filed March 24, 1923, by C. 0. North.

. Aldehydes and amines, particularly the aliphatic aldehydes and the pr 1mary aromatic amines, not only combine m equ1-Ino lecular proportions as well as in other ratlos as are set forth in the applications mentioned to produce reaction products but also react in the proportion of two molecules of Application filed April 8,

192a. serial'iqo. 100,684.

the amine to one molecule of an aldehyde to form'comfpounds known as dianilides which are classi ed among the substances known as Schiifs bases. The aldehyde reaction prod ucts of the dianilides have been more partlcularly described and specifically claimed as vulcanization accelerators by W. Scott in a 00%8I1d11lg application, Serial No. 32,188 filed Iay 22, 1925. The present invention is an Improvement upon the various copending applications mentioned and is a continuation 1n part of the one last indicated.

We have now found that. a rubber vulcanization accelerator may be manufactured by reacting butyric' aldehyde-dianilide or a like compound with heptaldehyde and the like in the manner as is now described. Such a material is preferably manufactured in steps and may be readily obtained by combining one molecular proportion (72 parts) of butyric aldehyde with two molecular proportions (186 parts) of aniline. I In this way butylidene-dianilide is obtained. Inasmuch as this combination takes place very readily and since thereaction is an exothermic one, the reacting mixture will heat up appreciably if the materials are all added at the same time. For this reason, it is preferable to supplysuitable stirring means in the reaction vessel andalso to provide internal or external heating or cooling means to the vessel in order to maintain the temperature of the mixture uniformly at any chosen. point. Ina'smuch as decomposition of the product or side reactions may take place if the temperature is allowed to become too high, it is preferable to add the aldehyde at such a rate that the stirring and cooling means will at all timesmaintain the temperature of the mixture at a point below 35 C.

To the butylidene-dianilide manufactured as above described, there is added one molecular proportion (114 parts) of heptal'dehyde. The reaction of this second aldehyde with the dianilide takes place somewhat more slowl than does the first reaction mentioned and t e temperature of the mixture is therefore more readily controlled. However, it is preferable to maintain the temperature at all times below 50 C. by employing the coolunder a vacuum.

' in means mentioned. In order that the altaldehyde reaction product of butylidenedianilide, is ready for incorporation intoa rubber mix in the manner as is hereinafter described. Other accelerators analogous to the one just described may be prepared in a similar manner by the use of other 1ngred1- go ents in place of those mentioned. Thus two molecular proportions of aniline (186 parts) are reacted and combined with one molecular proportion (45 parts) of acetaldehyde while maintainin the temperature below C.

25 The ethyli ine dianihde so obtained is then reacted with one molar proportion (1 14 parts) of heptaldehyde and the product maintained for some time at a temperature below 50 C. The water of condensation is then zo,s'eparated from" the material and any residual moisture is removed preferably by drying under a vacuum. The dried product is an orange yellow liquid having a specific gravity of 1.063. I

The heptaldehyde derivative of a Sclniffs base of the type obtained by interacting equimolecular proportions of an aldehyde and an amine may likewise be readily prepared. Thus two molecular proportions (186 parts) 40 of aniline are reacted with two molecular proportions (140 parts) of croton aldehyde while maintaining the mixture at temperatures below 60 C. In order to avoid over-heating the mixture by the heat evolved during, the

reaction, it is desirable to add the aldehyde in comparatively small portions with stirring over a period of time. After the aldehyde has been all added the water of condensation maybe removed if desired, although in this 6 case, as in the other examples as shown, such intermediate dr ing is not'absolutely necessary. The pro uct so obtained is then further reacted in the manner already described with one-half molar proportion (57 parts) of heptaldehyde and the resulting product dried. The product is a soft, dark red resin.

Products similar to those hereinbefore described may, of course, be prepared by the use of other ingredients than those particularly p 00 mentioned. Thus Schifis bases or aldehyde' derivatives thereof prepared by the reaction 7 of equi-molecular-proportions of the amine and aldehyde, or by the reaction of two molar parts of the amine with one molar part of aldehyde or by the reaction of three mols of period of time, with or without stirring p of 1.080. This material, which is a hep-.

the aldehyde with two mols of the amine or any other proportions may be obtained by reacting together in the necessary proportions rimary aromatic amines such as aniline, the toluidines, the xylidines and-the like with aldehydes preferably of the aliphatic series, such as formaldehyde, acetaldehyde, propion aldehyde, butyric aldehyde, heptaldehyde or with unsaturated aldehyde such as croton aldehyde, acrolein-aldehyde or with substitute aldehydes such as aldol and the like. The Schifis bases or the aldehyde derivatives thereof so obtained are then further reacted with heptaldehyde or other aldehyde in the manner as described. I

It is not, of course, necessary that heptaldehyde be used only to produce the final reaction product. An amine may be reacted first' with heptaldehyde to produce a SchiflVs base and this product may then be further reacted with butyric aldehyde, acetaldehyde, crotonaldehyde or with any other aliphatic aldehyde as desired. Although our invention, in its preferable form comprises the manufacture and use as an accelerator of vulcanizationof the heptaldehyde derivative of butylidinedianilide, the manufacture and use of any other material wherein heptaldehyde is used either in the preparationof the Schiffs base or the final aldehyde derivative prepared therefrom is within the scope of our present invention.

The materials hereinbefore mentioned may be used in the preparation of Vulcanized rubber as are shown by the following examples. If 0.5 parts of the heptaldehyde derivative of butylidine-dianilidebe added in the usual manner to a mix previously broken down on the mixing mills and comprising parts of pale crepe rubber, 5 parts of zinc oxide and 3.5 parts of sulphur and the mixture vulcanized in a press for approximately fortyfive minutes at the temperature given by 40 'shown 1n the above rubber composition, 0.5

arts of the material obtained by the reaction of heptaldehyde upon the reaction product of 2 mols of aniline with 1 mol of acetaldehyde. In a like manner, 0.5 parts of the heptaldehyde reaction product of croton-aldehyde-aniline may be employed in place of the accelerator specified in the above rubber hyde-amine reaction product which comprises.

mixture. Inthis case, it is found that a 'vulcanized rubber product possessing desirable commercial characteristics results after heating the rubber compound containing the accelerators mentioned for a period of about may likewise be employed in the manufacture of other vulcanized products than the one described. Other rubber mixtures adaptable to the use of the accelerators of the type herein described are apparent to those skilled in the art of rubber compounding.

It is to be understood that the examples given herein are illustrative only and are not imitative of our invention. Broadly, our invention comprises the formation of an aldehyde-amine reaction product wherein there is employed more than a single aldehyde, one of which is heptaldehyde. Preferably the invention comprises the reaction of an aliphatic aldehyde and a primary aromatic amine in other than equi-molecular proportions, such reaction being carried out in a series of steps or stages, in at least one of which steps heptaldehyde isemployed. The reaction products obtained by carrying out the rocess in the manner hereinbefore describe are complex products of undetermined constitution and chemical configuration. Our invention is to be understood as 'not limited by any theories or statements advanced by wa of explanation but is limited solely by t e claims appended hereto wherein we intend to claim all novelty inherent in our invention as is permissible in view of the prior art.

What we claim is: 1. The process of manufacturing an alde reacting more than one aliphatic aldehyde 5. The process of manufacturing an aldehyde-amine reaction roduct which comprises butylideneianilide with heptalde hyde-amine reaction product which comprises reactin substantially 72 parts of butyric aldehy e with 186 arts of aniline and reacting the product so 0 tained with substantially 114 parts of heptaldehyde.

7. The process of manufacturing an aldehyde-amine reaction product which comprises reacting butyric aldehyde and aniline in the ratio of substantially one molecular propor tion of butyric aldehyde to two molecular proportions of aniline, maintainin the temperature of the reacting materials elow 35 adding approximately 1 molecular proportion of heptaldehyde to the product so formed and drying the resulting product.

8. The aldhehyde-amine reaction product resulting from the treatment of an aromatic primary amine with'a plurality of aliphatic aldehydes in a series of steps, in at least one of which steps heptaldehyde is employed.

9. The aldehyde-amine reaction product resulting from the treatment of butylidenedianilide with heptaldehyde.

10. The aldehyde-aminereaction product resulting by treating the product obtained by reacting substantially two mols of aniline with one mol of butyric aldehyde and one mol of heptaldehyde.

Signed at Akron in the count of Summit and State of Ohio this 1st day 0 April, A. D.

CLAYTON OLIN NORTH.

INFIELD SCOTT.

with an aromatic primary amine in a series of steps, in at least one of which steps heptaldehyde is employed.

2. The process of manufacturing an aldehyde-amine reaction product which comprises combining more than one aliphatic aldehyde with an aromatic primary amine in other than equi-molecular roportions, said combination being carrie out in a series of steps, in at least one of which steps heptaldehyde is employed.

3. The process of manufacturing an aldehyde-amine reaction product which comprises reacting an aliphatic aldehyde with an aromatic primary amine to form an aldehyde derivative of a Schiiis base and reacting the said product with heptaldehyde.

4. The process of manufacturing an alde- I hyde-amine reaction product which comprises reacting butyric aldehyde with aniline and reacting the product t ereby obtained with heptaldehyde. 

